Iceland Within the Northern Atlantic, Volume 1

1 Cover

2 Title Page SCIENCES Geoscience , Field Director – Yves Lagabrielle Lithosphere-Asthenosphere Interactions , Subject Head – René Maury

3 Copyright First published 2021 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc. Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address: ISTE Ltd 27-37 St George’s Road London SW19 4EU UK www.iste.co.uk John Wiley & Sons, Inc. 111 River Street Hoboken, NJ 07030 USA www.wiley.com © ISTE Ltd 2021 The rights of Brigitte Van Vliet-Lanoë to be identified as the author of this work have been asserted by her in accordance with the Copyright, Designs and Patents Act 1988. Library of Congress Control Number: 2021932010 British Library Cataloguing-in-Publication Data A CIP record for this book is available from the British Library ISBN 978-1-78945-014-9 ERC code: PE10 Earth System Science PE10_5 Geology, tectonics, volcanology PE10_13 Physical geography PE10_18 Cryosphere, dynamics of snow and ice cover, sea ice, permafrosts and ice sheets

4 List of Abbreviations

5 Preface

6 Introduction

7 1 Iceland, in the Lineage of Two Oceans 1.1. Geographic and geodynamic context 1.2. Components of the North Atlantic domain 1.3. Geodynamic characteristics of Iceland 1.4. References

8 2 Iceland, an Emerging Ocean Rift 2.1. Mid-Atlantic Ridge and Icelandic hot spot interactions 2.2. Present-day deformations in Iceland 2.3. Iceland’s main structural features 2.4. Geothermal energy and hydrothermalism 2.5. References

9 3 Iceland, a Legacy of North Atlantic History 3.1. Bathymetry of the Northeast Atlantic domain and geoid anomalies 3.2. The North Atlantic and the continental breakup of Laurussia 3.3. The origin of Iceland 3.4. References

10 Conclusion

11 References

12 List of Authors

13 Index

14 Summary of Volume 2

15 End User License Agreement

1 Introduction Figure I.1. Iceland from Space (document Geographical Institute of Iceland/Landm... Figure I.2. (A) Icelandic stamp illustrating the discovery of Iceland by Irish m... Figure I.3. Traditional sheepfolds in southern Iceland with the volcano Hekla in... Figure I.4. (A) The Þingvellir graben, seen from an airplane (Þingvellir Nationa... Figure I.5. (A) The Hekla volcano (Brigitte Van Vliet-Lanoë©) and (B) its cartog... Figure I.6. Typical landscape of ancient basalts on the eastern coast of Iceland... Figure I.7. The eruption of the Eyjafjallajökull in 2010: its jökulhlaup (Reykja... Figure I.8. Sheep disturbed by the ash from the eruption (Flickr©) Figure I.9. Digital terrain model of Vatnajökull (black line: current cap bounda... Figure I.10. (A and B) Views of the Bárðarbunga caldera obliterated by ice durin... Figure I.11. Rim of the northern caldera of Grìmsvötn (Ragnar Sigurdsson©) Figure I.12. The Grìmsvötn volcano. (A) Initiation of the northward flow associa... Figure I.13. (A) The jökulhlaups of the Skafta River from the Grimsvötn in 1996 ... Figure I.14. (A) Fissural eruption of Krafla in 1980, along fractures arranged e... Figure I.15. Eruption of Krafla in 1980: hornitos on fractures and lava flows in... Figure I.16. (A) The submarine ridges of Kolbeinsey and (B) of Reykjanes (multib... Figure I.17. Trace of the Réttarnes seismic fault (1294 or 1732) in the Rangavel... Figure I.18. Destruction caused during the earthquakes of June 2000 in Bitra: (A... Figure I.19. Successive phases of an explosion of the Strokkur geyser, Geysir ge... Figure I.20. The Hofsjökull. Document made from radar images (CNES©). The calder... Figure I.21. (A) The Kerlingarfjöll surrounded by its glacial desert. (B) Perche... Figure I.22. A subglacial tabular volcano: the Herðubreið, north of Vatnajökull,... Figure I.23. Jökulsá á Kreppa north of Vatnajökull with hyaloclastite or tindar ... Figure I.24. A key Icelandic resource: water. (A) Bruarjökull outlet (the glacie...

2 Chapter 1 Figure 1.1. The Northeast Atlantic Ocean and the Labrador–Baffin axis (Gebco 201... Figure 1.2. (a) Geological map of Iceland, originally at 1/600,000e (H. Johaness... Figure 1.2. (b) Simplified geological map of Iceland (Icelandic Geographical Ins... Figure 1.3. Current morphology of Iceland. (a) A volcanic island shaped and occu... Figure 1.4. The northern part of the Mid-Atlantic Ridge, modified from (Müller e... Figure 1.5. The North Atlantic Igneous Province (from Storey et al. 2007; Thodar... Figure 1.6. Seismic imaging of the upper mantle at the Icelandic hot spot Figure 1.7. Seismicity in Iceland recorded by the SIL network between 1994 and 2... Figure 1.8. W-E topographic section of Iceland with its various morphological an... Figure 1.9. Global sea level evolution from the Eocene to the present day in rel... Figure 1.10. The Northwest Peninsula, western Iceland, and the strandflat

3 Chapter 2 Figure 2.1. Interactions between an oceanic ridge and a hot spot, and the specif... Figure 2.2. Plate boundaries in Iceland and major structural zones. Holocene vol...Figure 2.3. Earthquakes and structures related to the propagation of the Bárðarb...Figure 2.4. Seismic faults and microseismicity in the Tjörnes Fracture Zone (mod...Figure 2.5. Seismicity in the Tjörnes Fracture Zone (modified from Þorbjarnardót...Figure 2.6. Seismicity in the South Icelandic Seismic Zone (modified from Stefán...Figure 2.7. The faults of the earthquakes of June 17 and 21, 2000 (modified from...Figure 2.8. Surface traces of the June 17 and 21, 2000 earthquakes Figure 2.9. Seismicity in the Reykjanes Peninsula Figure 2.10. Sedimentary record of fault activity during deglaciation Figure 2.11. Plate boundary motions in Iceland (modified from Sigmundsson et al....Figure 2.12. Ages of the (projected) dykes along a transect N 106° E (40Ar/39Ar ...Figure 2.13. Tectonic evolution of Iceland since 8 My (according to Garcia 2003)...Figure 2.14. Volcanic systems of Iceland (modified from Einarsson and Sæmundsson...Figure 2.15. Krafla fissure swarm in the Leirhnjúkur sector, view toward the sou...Figure 2.16. West facing normal faults illustrating the step pattern in the Voga...Figure 2.17. The Vogar fissure swarm, Reykjanes Peninsula (modified from Villemi...Figure 2.18. Fissure swarms in the NVZ . (A) Kverkfjöll (modified from Plateaux ...Figure 2.19. Relationships between open fractures geometry at the surface and no...Figure 2.20. Vertical partitioning of the deformation in fissure swarms Figure 2.21. Normal faults and dykes in tertiary lava flows in Glaðheimar, Borga...Figure 2.22. Simplified models of the formation and growth of a normal rift faul...Figure 2.23. Development of a normal fault from en échelon joints (modified from...Figure 2.24. Along-strike profiles of vertical offsets for some faults in the Vo...Figure 2.25. Conceptual model of normal fault growth in the Icelandic rift (from...Figure 2.26. The Tjörnes Fracture Zone Figure 2.27. The Dalvik Line. (A) Morphostuctural traces in the Flateyjarskagi a...Figure 2.28. Cosismic loading deformations in Holocene glacio-marine sediments (...Figure 2.29. The Húsavík-Flatey Fault, on the coastal cliff, under the former ga...Figure 2.30. Geometry of the TFZ and junction with the Þeistareykir fissure swar...Figure 2.31. The Húsavík-Flatey Fault (HFF) in the Tjörnes Peninsula. (A) Aerial...Figure 2.32. Types of tectonic deformation encountered on the northern coast of ...Figure 2.33. Neogene and present-day faults and stresses in the Flateyjarskagi P...Figure 2.34.